Man, nuking it would turn it into shoe leather for sure, regardless of how well it's done.
So here's an experiment for the next time you cook rare. Before you let her see it, blindfold her and then cut some of the rare meat up on her plate & do the same with a piece you first cook more in a frying pan. (Don't use the MW because of what I said above.) Just be sure they're both about as hot. Have her eat one piece at a time by mixing and ask her to tell the difference for each one.
Reason I suggested it was because I did exactly that with my uncle & his well-done steaks.
He lived alone with my grandma for years, and she cooked the hell out of a good steak. It was after she died & he moved to AZ that I told him he didn't know what he was missing & coaxed him to play along with my experiment.
BUT...I never ruined a steak for it. Everything I gave him was rare, & he thought it was all good even though he guessed a couple bites were well done.
My hunting partner's wife always asked for well done when they came for dinner. I always cooked mine and his rare, and the girls medium rare. She always said it was close, but she liked it more grey. I almost jumped up one time and danced a jig, when my wife told her that there was no reason to ruin an entire steak by over-cooking, since she only ate half anyway and we would have to throw the other half away. She said our dogs wouldn't eat well done meat!!
She's never complained again and that was almost 20 years ago. I think I probably kissed my wife a couple extra times that night.